Multiconductor stranded remote-control cable

ABSTRACT

Multiconductor cable comprising a plurality of metal wires of high unit tensile strength, at least two wires fulfilling wholly or in part the function of an electrical conductor, a core withstanding the mechanical forces to which the cable is subjected when it is unwound, certain of the multiple wires being grouped to form a multi-strand single-channel conductor in which the mechanical strength and the electrical resistance are locally distributed at distinct location, said cable receiving a plastic protective coating obtained by extrusion or impregnation.

[ 51 July 11,1972

174/128 UX 174/126 UX 2,055,948 9/1936 Selquist....... 2,067,405 1/1937Mayne........

[$4] MULTICONDUCTOR STRANDED REMOTE-CONTROL CABLE [72] Inventors: RobertDulles-net, Chatillon-SousPBagneux;

...l74/l28 ...174/1l3X ...l74/l13X 3,339,012 8/1967 Hutchins,.1r

3,324,233 6/1967 Bryant........ Michele Sim, (iarcnne-colombes.3,433,890 3/1969 Gabriel etal both oi'Francc [73] Assignee:SocleteNationale lndustrlelle Aemepatlale,

3,261,908 7/1966 Roche et a1. .......l74/128 FOREIGN PATENTS ORAPPLICATIONS Paris, France July 6, 1970 [21] App1.No.: $2,178

344,194 3/1931 GreatBritain......................... 229,058 2/1925Great Britain....

[22] Filed:

Primary Examiner1.ewis H. Meyers Assistant Examiner-A. T. GrimleyAttorney-Karl W. Flocks [30] Foreign Application Priority Data July 7,1969 France.................1................6923008 ABSTRACTMulticonductor cable comprising a plurality of metal wires of at leasttwo wires fulfilling wholly or in part the function of an electricalconductor, a core withstanding the mechanical forces to which the cableis subjected when it is unwound, certain of the multiple wires being-strand single-channel conductor in which the mechanical strength andthe electrical resistance Rnmku R I n..

U m m m U m WL n u .1 m m 3 m m M a qdn U UH References Cited UNITEDSTATES PATENTS 12/1964 Schindler...............................

are locally distributed at distinct location, said cable receiving aplastic protective coating obtained by extrusion or impregnation.

174/116 SCllimgSDrlWlngflgures MULTICONDUCT OR STRANDED REMOTE-CONTROLCABLE The present invention relates to a stranded remote-control cablehaving a plurality of high tensile steel or alloy conductors, and moreparticularly to a remote-control cable in which the useful section of aconductor thereof is apportioned among a plurality of wires in order toimprove the overall mechanical strength of the cable without affectingits lightness.

The transmission over wires of remote-control commands issuing from afixed or mobile object such as an air, sea or land vehicle or a missile,offers, among other advantages by cornparison with wireless transmissionmeans, that of being impervious to jamming.

Wires used for this technique must satisfy many requirements arisingfrom a variety of electrical, mechanical, climatic, ageing andenvironmental difficulties.

Various trends have emerged, and techniques have gradually evolved fromthe single conductor to the composite conductor.

Initially cables consisted of a single light alloy (alumag) conductorwire with a diameter from 0. 15mm to 022mm, protected by a film ofalumina deposited by anodic oxidation and sealed by dipping inspecialbaths such as potassium bichromate baths. The danger of breakage ofthese wires as a result of the motions of command-guided missiles andthe precariousness of the protection provided by the anodic surfacetreatment of the wire led operators to use steel wires with a diameterfrom 0.15mm. to 022mm, provided with external protection such as enamelor a cotton covering. The missile was accordingly connected to theguidance station, usually by means of at least two wires of this kind,each several thousand meters long. The wires were wound to form twospools carried by the missile, and each of these two-single-strand wiresprovided both the electric circuit and the mechanical strength requiredfor the link. Thus, in the aeronautical field, this so-called two-spooltechnique was applied to the first generation of wire-guided missiles(the 85-10. 88-11 and 88-12 family of missiles). These wires had adiameter of 0. 1 5mm, 0.20mm and 022mm, and were enamelled and had afinal diameter included between 0.2lmm and 0.30mm.

As the performance requirements imposed in the art became morestringent, new solutions were evolved that gave satisfaction in varyingdegrees. With the increasing effort in aeronautical engineering toachieve, among other things, greater strength coupled with smaller sizeand weight, the single-spool" solution with a single interconnectingwire was adopted for missile guidance. This resulted in the design oftwo conductor remote-control cables.

The electric circuit, which must do as little mechanical work aspossible, invariably comprises two enamelled copper conductors which mayor may not be cloth-covered.

The necessary mechanical strength is obtained by adding a textilestructure of polyester, regenerated cellulose or silicone to the twoconductors. The textile threads may either run parallel to theconductors or be stranded in with the latter.

Such stranding makes for a more even structure and has the advantage ofreducing capacitive efl'ects.

An arrangement of the conductors to form parallel wires allows theconductors to be centered within the cable in order to better protectthem during the unwinding process.

The assembly is then covered in order to ensure better overall cohesion.It may be further covered with a suitably adapted plastic covering,obtained either by ordinary coating or by through-impregnation (invacuum or not), this latter application significantly improvingelectrical conductivity in the event of immersion in water.

Although this new technique resulted in very notable improvements, itwas insufficiently reliable because of the low resistance to the effectsof contact or environment, which was in turn due to the cascade typestructure.

The present invention accordingly provides a new cable obtained bystranding a plurality of metal wires made of veryhigh-tensile steel orspecial alloys, for example, that perform wholly or partly the functionof conductors and offer the various advantages already available in theprior art, but with less danger of rupturing.

Further particulars and advantages will emerge from the descriptionwhich follows of several non-imitative exemplary embodiments of theinvention, given with reference to the accompanying drawings, in which:

FIG. 1 is an overall view of a stranded cable according to theinvention;

FIG. 2 is a section taken through the line IIII OF FIG. 1, and

FIGS. 3 to 5 are sectional views corresponding to FIG. 1, showingalternative embodiments.

Reference to FIG. 1 shows a cable 10 comprising a plurality ofconducting wires 1 to 6 stranded about a core 7. The wires 1, 2, 3 ofone group thereof are crossed by the same current, the return path ofwhich is provided by the other group of wires 4, 5, 6 of the pair ofconductors of single-channel cable 10.

The stranded cable 10 is encased in a coating or cover 8, or in both (acovering and an outer coating).

The wires 1 to 6 have a steel core and are coated with possiblyelectrolytic copper over the annular portion 9.

An insulating envelope 11, obtained by enamelling for example, isprovided over the copper.

The core wire 7 is made of steel and its main function is to withstandthe mechanical forces to which the cable is subjected as it is unwound.

Reference is next had to FIG. 3 for a similar arrangement of two pairsof conductors 12, 13 and I4, 15, respectively, wherein three alignedwires l6, l7 and 18 provide the overall mechanical strengththerebetween, the complete cable being encased at 19 in a textile coverand coating.

It was found that a multiconductor cable according to this invention issatisfactory for transmitting commands to a command-guided missile evenin the absence of copper. FIG. 4 shows four conductors arranged in twogroups 20, 21 and 22, 23, respectively, these conductors being made ofsteel and covered with insulation 1 l.

Whereas the single wires of the prior art were wires of 0. l 5 to 022mmgauge, the clustered wires of the conductor pairs according to thisinvention are wires with diameters of less than 0.05 to 0.1mm, the unitelectrical resistance of which is almost the same and the overallmechanical strength of which is considerably greater for substantiallythe same total cable weight.

The core 24 in the center of the wires is a textile core.

Reference is lastly had to the alternative embodiment of FIG. 5, whichshows seven clustered steel conductors 25, insulated by enamelling andcovering, the entire assembly being through-impregnated in vacuumsubsequent to stranding, in accordance with conventional techniques.

The conducting wires 1 to 6 and 12 to 15 help to increase the mechanicalstrength of the cable stranded about the cores 7 and 16 to 18. Thesewires are galvanized, coppered or otherwise protected against corrosion.The wires 20 to 23 and 25 alone assure the electrical conductivity andthe mechanical strength of the cable. Preferably, they are made ofvery-hightensile steel of good conductivity.

The wires are stranded sufficiently tightly in helical fashion, with apitch of a few millimeters, over variable lengths that may extend toseveral thousand meters. This tightly wound configuration ensures cablehomogeneity, so that in the event of rupture of one of the conductorsthe cable as a whole should retain its structural stability.

The stranded cable thereby obtained is possibly covered subsequently, inwhich case it is impregnated with a plastic which is thermosetting orthermoplastic whereby to obtain a structure possessing the requiredattributes of tightness, flexibility, electrical strength and overallgauge of the finished cable.

A few examples of stranded cables according to this invention are givenbelow EXAMPLE I The cable includes three parallel steel wires 0.1mm indiameter, with a tensile strength included between 250 and 300 ltg/mmthat assures in particular the mechanical strength of the cable.

These three single wires extend parallel to one another in the sameplane and receive, on either side of said plane, parallel to themselves,two wires with a steel core of identical grade (of 0.05mm diameter),which are copper-coated (outer diameter: 0.07mm) and covered externallywith an insulating coating (outer diameter: 0.1mm), after possiblecovering of said wires.

Subsequent to the precedingly described stranding operation, this set ofseven wires is covered and impregnated to the final outer diameter(035mm to 0.40mm approximately). The cable obtained thus possesses therequired mechanical characteristics:

Weight: 0.380 g/rn Resistance: 4.5 Q /m Mechanical strength: 8 daN Yieldstrength: 2 percent EXAMPLE 2 A single 0.1mm diameter steel wire assuresthe mechanical strength primarily and is surrounded by six 0.05mmdiameter coppered and insulated steel core wires. Subsequent tostranding, the covering and the top impregnation coating are effected inthe manner described precedingly. Such a cable has the followingphysical characteristics:

Mechanical strength: 8da N Weight: 0.360 g/meter Resistance: Q/m

EXAMPLE 3 The cable comprises in this case four single insulated steelwires arranged parallel to a textile core which contributes to theoverall mechanical strength and which is made of polyester, cellulose orsilicone. Subsequent to stranding, the entire assembly is covered andimpregnation-coated.

It goes without saying that changes may be made in the embodimenthereinbefore described for exemplary purposes, without departing fromthe scope of the invention as set forth in the appended claims.

We claim:

1. A remote-control multiconductor cable for commandguided missilescomprising a steel core means to withstand the mechanical forces towhich the cable is subjected when it is unwound, at least two electricalconductor wire means wound helically about said core means to fonn amulti-strand single channel conductor with mechanical strength andelectrical resistance locally distributed at distinct locations,

each said electrical conductor wire means being a steel wire meanshaving a diameter substantially in the range of 0.05mm to 0. lm andhaving a copper coating thereon and further coated with an insulatingdeposit whereby the electrical resistivity of said electrical conductorwire means is relatively lower and the mechanical strength and yieldstrength of the cable as a whole is relatively higher than that of asingle wire of identical crosssection.

2. A cable according to claim 1, characterized in that the stranding iseffected at a sufiiciently close pitch of the order of a fewmillimeters, whereby cable homogeneity is obtained by the tightness ofthe winding and the cable retains its structural stability in the eventof rupturing of a strand.

3. A cable according to claim 1, characterized in that said cable has acovering and a plastic protective coating.

4. A cable according to claim 3, characterized in that the protectiveplastic is selected from the group consisting of polyvinyl chloride,nylon and silicone.

5. The remote-control cable according to claim 1 further characterizedby the cable including said core means and said electrical conductorwire means having a weight of not more than .380 grams per meter.

1 l II t

1. A remote-control multiconductor cable for command-guided missilescomprising a steel core means to withstand the mechanical forces towhich the cable is subjected when it is unwound, at least two electricalconductor wire means wound helically about said core means to form amulti-strand single channel conductor with mechanical strength andelectrical resistanCe locally distributed at distinct locations, eachsaid electrical conductor wire means being a steel wire means having adiameter substantially in the range of 0.05mm to 0.1mm and having acopper coating thereon and further coated with an insulating depositwhereby the electrical resistivity of said electrical conductor wiremeans is relatively lower and the mechanical strength and yield strengthof the cable as a whole is relatively higher than that of a single wireof identical cross-section.
 2. A cable according to claim 1,characterized in that the stranding is effected at a sufficiently closepitch of the order of a few millimeters, whereby cable homogeneity isobtained by the tightness of the winding and the cable retains itsstructural stability in the event of rupturing of a strand.
 3. A cableaccording to claim 1, characterized in that said cable has a coveringand a plastic protective coating.
 4. A cable according to claim 3,characterized in that the protective plastic is selected from the groupconsisting of polyvinyl chloride, nylon and silicone.
 5. Theremote-control cable according to claim 1 further characterized by thecable including said core means and said electrical conductor wire meanshaving a weight of not more than .380 grams per meter.